<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.DriverManager" %>
<%@ page import="java.sql.PreparedStatement" %>
<%@ page import="java.sql.ResultSet" %><%--
  Created by IntelliJ IDEA.
  User: 发
  Date: 2020/10/9
  Time: 10:03
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
  request.setCharacterEncoding("utf-8");
  String username =request.getParameter("username");
  String password =request.getParameter("password");

  //加载数据库驱动
  Class.forName("com.mysql.jdbc.Driver");

  //建立数据库连接
  String url = "jdbc:mysql://localhost:3306/book";
  Connection connection = DriverManager.getConnection(url,"root","root");

  //sql模板
  String sql = "select * from user where username = ? and password = ?";

  //使用preparedstatement对象执行sql语句
  PreparedStatement ps = connection.prepareStatement(sql);

  //赋值语句
  ps.setString(1,username);
  ps.setString(2,password);

  ResultSet rs = ps.executeQuery();

  if(rs.next()){
    //表示登陆成功
    session.setAttribute("username",username);
    response.sendRedirect("home.jsp");
  }else{
    //表示登录未成功
    out.print("登陆失败，3秒后跳转到登录页面");
    response.setHeader("Refresh","3;url=login.jsp");
  }

%>